In general, a liquid crystal device is often constructed by producing two substrates, a first substrate and a second substrate, each of which has an electrode on its surfaces. A seal material, made of photo-setting resin or the like, is placed on the inside surface of the first substrate so as to surround a display area, and the second substrate is bonded to the first substrate through the seal material, thereby producing a liquid crystal cell with a predetermined gap (cell gap) between the substrates.
In bonding the aforementioned substrates together, the substrates are adhered together with an unhardened seal material, and the adhered substrates are pressed by a certain amount in order to temporarily press-bond them together. Then, in order to position the substrates parallel to each other and form the cell gap with precision, a jig is used to fix the substrates while applying pressure to the substrates. When the seal material is one having a photo-setting property, the seal material is hardened by irradiating light thereto.
In this case, and particularly in the case where a liquid crystal device with a large liquid crystal display area is to be constructed, a method may be used, in which transparent spacers with diameters formed in correspondence with the cell gap are not uniformly disposed within the liquid crystal display area between the substrates. The first substrate is placed upon the second substrate for pressing, with the cell gap maintained by the spacers. Here, the spacers may be provided in the seal material.
For liquid crystal projectors, video finders, or the like, which have a liquid crystal display area that is small but a very fine display quality, spacers may be provided in the seal material to define the cell gap, instead of being not uniformly provided within the liquid crystal display area to increase the brightness and accuracy of the display.
FIG. 9 is a planar view of a small liquid crystal panel for a liquid crystal projector. A seal material 11 is placed onto the surface of a transparent element substrate 10, made of glass or the like, so as to surround a liquid crystal display area A. An opposing substrate 20, which is slightly smaller than the element substrate 10, is placed on the element substrate 10 having the hardened seal material 11 placed thereon to bond them together. An opening 11a is previously formed in the seal material 11. Liquid crystal is injected into the liquid crystal display area A from the opening 11a, after which the opening 11a is sealed by a sealing material 12.
In the above-described conventional liquid crystal panel producing process, it is necessary to bond the element substrate 10 and the opposing substrate 20 together with the seal material 11. In this case, as shown in FIG. 6A, the seal material 11 is placed on the inside surface of the element substrate 10 in such a manner as to surround the liquid crystal display area, using a dispenser or the like. Then, as shown in FIG. 6B, the opposing substrate 20 is placed on the element substrate 10 through the seal material 11.
However, in conventional producing methods, when the opposing substrate 20 is being placed onto the element substrate 10, the opposing substrate 20 is slightly tilted so that it frequently contacts the seal material 11 from the side, as shown in FIG. 6B. Thereafter, as shown in FIG. 6C, even the element substrate 10 and the opposing substrate 20 are positioned substantially parallel to each other, the part of the seal material 11, which is first contacted by the opposing substrate 20 (or the left sectional portion of the seal material in FIG. 6), is deformed, reducing the sealing performance of this portion of the seal material with respect to the opposing substrate 20. When sealing performance of the seal material 11 is reduced, the liquid crystal panel's durability, shock resistance, and the like are reduced. In extreme cases, leaks occur at the liquid crystal sealing portion that must be firmly sealed by the two substrates and the seal material.
In view of the above-described problems, it is an object of the present invention to provide a novel structure and producing method of a liquid crystal device, in which a seal material is not easily deformed, even when a substrate being bonded to another substrate contacts the seal material from one side, so that the sealing property of the seal material is not affected, and a uniform cell thickness distribution can be obtained.